'rilE PEEDACEOI'S niTTXG BEETLES. 207 



KEY TO SUBFAMIT.IKS (llf DYTISCJDiE. 



«■ Episternum of metatliorax not reaching the middle coxal cavity. (Fig. 



106.) Subfamily I. Feagmentati, p. 207. 



«". Episternum of metathorax reaching the middle coxal cavity. (Fig. 



107.) Subfamily II. Complicati, p. 210. 



In the accompanying cuts, Fig. 106 rep- 

 resents a diagram of a portion of the under 

 surface of Laccophilus, which belongs to 

 the subfamily Fragmeiifafi, cc being the 

 middle coxal cavity. It will be seen that '*^ ' 

 the mesosternal epimeron {ms. epm.) ar- 

 ticulates at its inner end with the meta- 

 sternum {)iit.). and thus cuts off the 

 metasternal episternum {mt. eps.) from 

 the coxal cavity. In Fig. 107, however, 

 which is a diagram of similar parts of "*" a.._Fig. loe^ b.-Kg. io7. 

 ColymhUes of the subfamily Complicati, (After wickham.) 



the mesosternal epimeron does not articulate with the metasternum, 

 and thus allows the episternum of the latter to reach the cavity. 

 These features are not, as a rule, difficult to make out, and form 

 the basis of the modern classification of the family, by Dr. Sharp. 



Subfamily I. FRAGMENTATI. 



The North American members of this subfamily are divided 

 among two tribes, both of which are represented in the Indiana 

 fauna. In all the species the scutellum is invisible. 



KEY TO TKIBES OP FRAGMENTATI. 



a. Hind coxits longer near the middle of the body ; presternum dilated be- 

 hind, truncate or nearly so. Tribe I. Notebini, p. 207. 

 aa. Hind eox:e longer near the sides of the liorty ; prosternal process coni- 

 liressed. reaching the metasternum. 



Tribe II. Laccophilini, p. 209, 



Tribe I. NOTEKINI. 



The mcmliers of this tribe are all small beetles having the body 

 convex, obtuse in front and pointed behind; front and middle 

 tarsi five-.jointed ; apex of front tibia" with a curved spur or hook. 

 Two genera occur in Indiana. 



KEY to INDIANA GENERA OF NOTERINI. 



a. Last joint of maxilhiry palpus bifid or emarginate; prosternal process 

 not broader than long ; hind tibiiB less dilated ; length less than 3 mm. 



I. Canthydbus. 

 114—23402] 



